U.S. patent application number 14/650459 was filed with the patent office on 2015-12-03 for medication injector with near-empty alert.
This patent application is currently assigned to Merck Sharp & Dohme Corp.. The applicant listed for this patent is Peter A. BASILE, Jeffrey C. GIVAND, MERCK SHARP & DOHME CORP., Steven Carl PERSAK. Invention is credited to Peter A. Basile, Jeffrey C. Givan, Steven Carl Persak.
Application Number | 20150343157 14/650459 |
Document ID | / |
Family ID | 50934836 |
Filed Date | 2015-12-03 |
United States Patent
Application |
20150343157 |
Kind Code |
A1 |
Basile; Peter A. ; et
al. |
December 3, 2015 |
MEDICATION INJECTOR WITH NEAR-EMPTY ALERT
Abstract
A medication injector that has an alert indicator that alerts
the user when the medication injector is approaching near the end
of its medication supply is disclosed. The alert indicator gives
the user an opportunity to make preparations to obtain additional
medication for the injector if there is an insufficient amount of
medication in the injector to enable the user to dispense the
required dosage amount with the next injection. Initially, the
alert indicator is not visible to the user, but becomes visible to
the user when the injector is near empty.
Inventors: |
Basile; Peter A.;
(Bloomsbury, NJ) ; Givan; Jeffrey C.; (North
Wales, PA) ; Persak; Steven Carl; (Basking Ridge,
NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BASILE; Peter A.
GIVAND; Jeffrey C.
PERSAK; Steven Carl
MERCK SHARP & DOHME CORP. |
West Point
Rahway |
PA
NJ |
US
US
US
US |
|
|
Assignee: |
Merck Sharp & Dohme
Corp.
Rahway
NJ
|
Family ID: |
50934836 |
Appl. No.: |
14/650459 |
Filed: |
December 5, 2013 |
PCT Filed: |
December 5, 2013 |
PCT NO: |
PCT/US2013/073212 |
371 Date: |
June 8, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61735225 |
Dec 10, 2012 |
|
|
|
Current U.S.
Class: |
604/506 ;
604/111 |
Current CPC
Class: |
A61M 5/31583 20130101;
A61M 5/5086 20130101; A61M 5/31535 20130101; A61M 5/31578 20130101;
A61M 5/31541 20130101; A61M 2005/3125 20130101; A61M 5/32 20130101;
A61M 2205/584 20130101; A61M 5/31511 20130101; A61M 5/3155
20130101; A61M 2005/3126 20130101 |
International
Class: |
A61M 5/50 20060101
A61M005/50; A61M 5/32 20060101 A61M005/32; A61M 5/315 20060101
A61M005/315 |
Claims
1. A medication injector for injecting a medication comprising: a
housing having a longitudinal axis and an internal viewing portion
for viewing inside the housing; a piston rod in the housing and
oriented in the direction of the longitudinal axis; an alert
indicator on or carried by the piston rod for signaling that the
injector is approaching the end of its medication supply, the alert
indicator having a hidden position in which it is generally not
visible through the internal viewing portion and a visible position
in which it is visible through the internal viewing portion, the
alert indicator moving from the hidden position to the visible
position when the piston rod is advanced distally a predetermined
distance.
2. The injector of claim 1, further comprising a medication
cartridge containing a medication and a stopper, wherein the piston
rod drives the stopper distally in the medication cartridge to
dispense the medication.
3. The injector of claim 2, further comprising a needle at the
distal end of the injector.
4. The injector of claim 1, wherein the internal viewing portion of
the housing is a window in the housing.
5. The injector of claim 1, wherein the internal viewing portion of
the housing is a transparent part of the housing.
6. The injector of claim 1, wherein the piston rod has an upper
threading portion and a lower threading portion that is located
distal to the upper threading portion, the upper threading portion
having a thread form that is different than the thread form on the
lower threading portion; and wherein the alert indicator is a
signal nut having a threaded hole through which the piston rod is
inserted, the signal nut mating with and being rotatable on the
lower threading portion of the piston rod, but interfering with and
not rotatable on the upper threading portion of the piston rod.
7. The injector of claim 6, wherein the signal nut is initially
located on the lower threading portion of the piston rod at a
position where the signal nut is in the hidden position and is not
visible through the internal viewing portion, and wherein the
signal nut moves relatively proximally on the piston rod as the
piston rod is driven distally.
8. The injector of claim 7, wherein the signal nut is held
stationary in the housing while on the lower threading portion, and
wherein the signal nut travels distally with the piston rod once
the upper threading portion reaches the signal nut.
9. The injector of claim 6, wherein the signal nut has a different
color than an external color of the housing around the internal
viewing portion.
10. The injector of claim 6, wherein the length of the piston rod
encompassed by lower threading portion is greater than the length
of the piston rod encompassed by the upper threading portion.
11. The injector of claim 10, wherein the lower threading portion
encompasses a majority of the length of the piston rod.
12. The injector of claim 6, wherein the signal nut has flexible
arms that flex outward.
13. The injector of claim 1, wherein the piston rod has an upper
portion and a lower portion that is distal to the upper portion,
wherein the alert indicator is a different coloring on the upper
portion than on the lower portion of the piston rod.
14. The injector of claim 1, wherein the medication is insulin.
15. The injector of claim 1, wherein the injector has a dosage
scale for indicating the amount of medication in the injector,
wherein the dosage scale is marked in increments of 30 units or
less.
16. The injector of claim 15, wherein the maximum amount measured
by the dosage scale is the last 120 units or less of medication
amount.
17. The injector of claim 15, wherein a lower range of the dosage
scale is shown in a different color than an upper range of the
dosage scale.
18. The injector of claim 15, wherein a lower range of the dosage
scale has markings in finer resolution increments than an upper
range of the dosage scale.
19. A method of administering a dosage amount of medication,
comprising: using a first medication injector comprising: (a) a
housing having a longitudinal axis and an internal viewing portion
for viewing inside the housing, (b) a piston rod in the housing and
oriented in the direction of the longitudinal axis, (c) a first
medication cartridge containing a medication, and (d) an alert
indicator on or carried by the piston rod for signaling that the
first medication injector is approaching the end of its medication
supply; visualizing the alert indicator of the first medication
injector; retrieving a second medication injector or a second
medication cartridge for loading in the first medication injector;
and performing a first injection with the first medication injector
to administer part of the dosage amount of the medication; to
complete the dosage amount, performing a second injection with the
second medication injector or with the first medication injector
loaded with the second medication cartridge.
20. The method of claim 19, wherein the second medication injector
or a second medication cartridge is retrieved from refrigerated
storage.
Description
BACKGROUND OF THE INVENTION
[0001] (1) Field of the Invention
[0002] The present invention relates to injectors for administering
a medication.
[0003] (2) Description of Related Art
[0004] Various types of injectors for administering a medication
are known. In some cases, the injector is capable of holding
medication sufficient for multiple doses. For each dose, the user
selects the amount of medication to be injected, for example by
dialing a dose set knob, and then injects that selected dose. This
may be done for multiple doses over a period of time, until all of
the medication in the injector has been dispensed.
[0005] Such injectors may be useful for various types of
medication. For example, many diabetic patients self-inject insulin
multiple times each day using an injector device or pen. Many such
pens are operated by the patient dialing the required dose and then
self-injecting the selected dosage amount. Because the patient is
constantly using an injector pen on a daily basis, users will
frequently require changing to a new injector when the insulin
supply is exhausted. Sometimes, as the injector pen is approaching
the end of its insulin supply, the injector does not contain enough
insulin to provide the full dose for this last injection.
[0006] In many injectors, as the dose is being selected or dialed,
the amount of the selection is indicated to the user, for example
on a scale that is visible through a window of the injector
housing. As the selected dose is being injected, the scale returns
in accordance with the amount injected. Thus, when the full amount
of the selected dose is injected, the scale returns from the
selected amount back to the zero position. If less than the full
amount of the selected dose is injected, the scale returns only by
the amount that has been injected, such that after the partial
injection the scale shows the difference between the amount
selected and the amount injected.
[0007] Conventionally, there have been two ways of handling the
situation when there is only a partial dose remaining in the
injector pen. In the first way, the user sets the dose the same way
as the prior doses, by dialing the dosage knob to the full amount
of the desired dose. When only a partial dose of medication remains
in the pen, this set dose exceeds the remaining amount of
medication. The user may not be aware that the set dose exceeds the
available medication. When the user injects the medication, the
delivery mechanism will stop when the full available amount of
medication has been delivered, because the piston rod inside the
injector cannot advance any further. In this case, the scale of the
injector pen indicates the portion of the selected dosage amount
that was not dispensed, which the user must supplement with an
additional injection from a new injector pen.
[0008] In the second way, an "active-stop" injector, the dosage
knob prevents the user from dialing a dose that is greater than the
amount of medication remaining in the pen. Thus, the injector
itself will indicate to the user that only a partial dose remains,
which indication will occur at the time the user attempts to set a
dose higher than the amount of remaining medication.
[0009] In using both types of injector pens, the user should
perceive that the old injector pen is near empty and have the new
injector pen ready to inject the supplemental make-up dose. But if
the user only becomes aware of the last remaining dose too late,
such as only when the injector is empty or only upon attempting to
dial a dose, the user may not have prepared the new injector pen
for use. Because insulin pens are commonly stored in the
refrigerator for preservation, an unaware user would have to
retrieve a new injector from the refrigerator and administer a cold
injection for the supplemental dose, which is uncomfortable.
Otherwise, the user will have to wait until the new injector pen is
warmed to room temperature, which can be inconvenient.
[0010] In addition, many "active-stop" injector pens have numerous
parts. Certain "active-stop" injector pens can be relatively
expensive to manufacture.
BRIEF SUMMARY OF THE INVENTION
[0011] The medication injector of the present invention informs the
user when the medication injector is approaching near the end of
its medication supply. This gives the user an opportunity to make
preparations if there is an insufficient amount of medication to
dispense the required dosage amount with the next injection.
[0012] With respect to terminology, the medication injector of the
present invention has a proximal end and a distal end. "Distal"
refers to the direction towards the patient when the injector is
applied to the patient, i.e., the needle end; "proximal" refers to
the opposite direction. The terms "upper" and "proximal" with
respect to the medication injector are used interchangeably herein;
the terms "lower," "forward," and "distal" with respect to the
medication injector are used interchangeably herein.
[0013] The medication injector comprises a housing for containing a
medication cartridge (e.g., ampoule or syringe) inside the housing.
The housing may be a single component or multiple components that
are fitted together. The injector may have other housing components
such as an inner housing(s) or sleeve(s). The medication injector
may be provided with or without the medication cartridge loaded
inside the housing. In some embodiments, the housing houses at
least the medication cartridge. For example, the housing may be a
cartridge holder portion that holds the medication cartridge.
[0014] The medication injector is designed for administering
multiple doses of the medication. The medication injector may be
disposable, i.e., intended to be disposed when the medication
cartridge is empty; or the injector pen may be reusable, i.e., it
can be reloaded with another medication cartridge when empty. The
medication cartridge may include a stopper and/or needle.
[0015] There is a piston rod located in the housing oriented in the
longitudinal direction. The piston rod is engaged with a drive
mechanism that advances the piston rod. The piston rod may be
threaded. In certain embodiments, the drive mechanism rotates the
piston rod such that it is driven downward in a screwing fashion.
In other embodiments, the drive mechanism drives the piston rod
downward without rotation of the piston rod. In either case, the
piston rod pushes against a stopper inside the medication
cartridge, causing medication to be dispensed out of the cartridge.
The piston rod may interact with the stopper in any suitable
fashion, e.g., they may together be a single unit, the piston rod
may push directly against the stopper, or the piston rod may have a
flange or be attached to a separate part that pushes against the
stopper. The drive mechanism can be any suitable mechanism used in
injection devices, and may include conventional components such as
spring(s), lever(s), clutch(es), sleeve(s), latch(es), brake(s),
ratchet(s), threaded insert(s), etc. The injection mechanism may be
operated manually or automatically.
[0016] The piston rod has or carries an alert indicator that
signals to the user that the injector is near empty. The housing
has an internal viewing portion that allows the user to see inside
the housing. Initially, the alert indication is not visible through
the internal viewing portion. But after the piston rod is driven
downward a predetermined distance, the alert indicator becomes
visible through the internal viewing portion. For example, the
internal viewing portion can be a window in the housing, and the
alert indicator is brought into view through the window.
[0017] In another example, part of the housing can be opaque and
the internal viewing portion is a part where the housing is
transparent. The alert indicator may become visible as it moves
down from behind the opaque part to the transparent part of the
housing. Thus, the alert indicator has a hidden position in which
it is generally not visible through the internal viewing portion,
and the alert indicator has a visible position in which it is
visible through the internal viewing portion, with the alert
indicator moving from the hidden position to the visible position
when the piston rod is advanced distally a predetermined distance.
The injector is designed so that the alert indicator becomes
visible when a certain amount of medication remains in the
injector. For example, in some embodiments, this alert indicator
will become visible when the medication injector has less than 60
units of medication remaining.
[0018] In one embodiment, the alert indicator is a signal nut on
the piston rod that is initially located on a lower threading
portion of the piston rod at a position where the signal nut is not
visible to the user. On this lower threading portion, the piston
rod is rotatable relative to the signal nut. The signal nut may
have any suitable shape, such as square, hexagonal, or round (e.g.,
a disc).
[0019] As the piston rod is driven forward during actuation of the
medication injector, the rod freely rotates through the signal nut,
which is held stationary inside the housing. The signal nut may be
held in place inside the housing by any suitable mechanism. For
example, the signal nut may have spring arms that flex radially
outward against a stationary component of the medication injector
(e.g., inside wall of the housing).
[0020] Because the signal nut is held stationary, as the piston rod
is fed through the signal nut, the signal nut travels in a relative
upward direction on the piston rod as the piston rod is driven
downward (although the signal nut remains stationary relative to
the housing). Once the piston rod has been advanced to a position
where only a certain amount of medication remains, a predetermined
position on the piston rod reaches the signal nut and the signal
nut becomes rotationally locked to the piston rod (such that the
signal nut cannot move further toward the proximal end of the
piston rod). Being rotationally locked to the piston rod, the
signal nut now travels downward with the piston rod as the piston
rod is driven downward. With this downward movement of the signal
nut, it becomes visible to the user, indicating to the user that
the medication injector is close to exhausting its supply of
medication. The signal nut may have a color that makes it more
conspicuous to the user. For example, the signal nut may be red or
another suitable color, such as a color that is different from an
external color of the housing.
[0021] The following describes an embodiment of a mechanism by
which the signal nut may become rotationally locked to the piston
rod. In this embodiment, the piston rod has an upper threading
portion and a lower threading portion, with the thread form
(cross-section shape of the threading) on the upper threading
portion being narrower than the thread form on the lower threading
portion. The signal nut has a hole through which the piston rod is
inserted. This hole is threaded with a thread form that mates with
the thread form on the lower threading portion of the piston rod,
but interferes (does not mate) with the thread form on the upper
threading portion of the piston rod. In some cases, the length of
the piston rod having the wider thread form (on the lower threading
portion) is greater than the length of the piston rod having the
narrower thread form (on the upper threading portion). For example,
a majority of the length of the piston rod may have the wider
thread form (on the lower threading portion).
[0022] In this embodiment, the signal nut is initially located on
the lower threading portion of the piston rod with the wider thread
form. However, as the piston rod is fed downward through the signal
nut, which remains stationary at this stage, the upper threading
portion of the piston rod having the narrower thread form
approaches the signal nut. But because the internal threading on
the signal nut interferes with the thread form on the upper
threading portion of the rod, the upper threading portion of the
rod cannot rotate through the signal nut (i.e., an interfering
interaction). As a result, the signal nut becomes rotationally
locked to the piston rod and travels axially downward with the
piston rod. This downward travel of the signal nut brings it into a
position where it is visible to the user, indicating to the user
that the medication injector is near-empty.
[0023] Various components involved in this mechanism can be
configured to give the near-empty signal at the appropriate time,
including the location of transition to the narrower thread form on
the upper threading portion of the piston rod, the length of the
piston rod, the width of the signal nut, the location and size of
the view window, etc. The injector may be designed so that the
alert indicator becomes visible when less than a single dose of
medication remains in the injector. In some embodiments, this
signal nut will become visible when the medication injector has
less than 60 units of medication remaining.
[0024] In an alternate embodiment of the medication injector, the
alert indicator is on the piston rod or is a part of the piston rod
itself. For example, the piston rod may have a different color on
an upper portion than a lower portion. Appearance of the upper
portion in a different color signals that the injector is near
empty. As the piston rod advances downward, the alert indicator on
the piston rod is brought into a position where it is visible to
the user, alerting the user that the medication injector is
near-empty. The indicator may be made visible through an internal
viewing portion, as described above.
[0025] Because the medication injector of the invention is designed
to alert the user when it is near-empty, it may have a finer
resolution dosage scale than conventional medication injectors.
Typical insulin injectors deliver a maximum single dose of 60
units, and, as such, may have dosage scale markings in coarse
increments, such as 60 units.
[0026] In contrast, in some embodiments, the medication injector of
the invention may have a dosage scale with finer increments to
inform the user more precisely about the dosage amount remaining
when the medication injector is near-empty. For example, the dosage
scale may include markings with increments of 20 units or finer, or
in some cases, in increments of 10 units or finer. With this finer
resolution dosage scale, the user can be better informed about the
amount of medication remaining.
[0027] In another embodiment, the present invention provides a
method of administering a dosage amount of medication using a
medication injector. The method comprises visualizing an alert
indicator in the medication injector. After visualizing the alert
signal, the user retrieves another (second) medication cartridge
for loading in the medication injector or another (second)
medication injector. The user performs an injection with the
(first) medication injector to administer part of the dosage amount
of the medication. To complete the dosage amount, the user then
performs another injection with the medication injector loaded with
the second medication cartridge or with the second medication
injector.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 shows a piston rod according to an embodiment.
[0029] FIG. 2 shows a close-up view of the two different thread
forms on the piston rod of FIG. 1.
[0030] FIG. 3 shows the threading groove on the piston rod of FIG.
1 if it were to be unwound into a straight path.
[0031] FIG. 4 shows a signal disc according to an embodiment.
[0032] FIG. 5 shows a cross-section view of the internal threading
of the signal disc in FIG. 4.
[0033] FIG. 6 shows the piston rod of FIG. 1 inserted through the
signal disc of FIG. 4.
[0034] FIG. 7A shows a cross-section view of a medication injector
according to an embodiment.
[0035] FIG. 7B shows a side view of the lower portion of the
medication injector.
[0036] FIG. 8 shows the injector of FIG. 7 after several
injections.
[0037] FIG. 9A (cross-section) and FIG. 9B (side view) show the
injector of FIG. 7 when it is near empty.
[0038] FIG. 10 shows a cartridge holder portion of a medication
injector according to another embodiment.
[0039] FIG. 11 shows a cartridge holder portion of a medication
injector according to yet another embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0040] An example embodiment of the invention will now be
described. FIG. 1 shows an example of a piston rod 10. Piston rod
10 is threaded and has two different thread forms. On the lower
threading portion 12 of rod 10, the thread form is a square shape.
On the upper threading portion 14 of rod 10, the thread form is a
narrower width, V-shape. The threading on lower portion 12 is
continuous with the threading on upper portion 14. The transition
16 between the two thread forms may be gradual or abrupt.
[0041] FIG. 2 shows a close-up view of the two different thread
forms at the transition point 16. As seen here, the thread form 22
on the upper threading portion 14 of piston rod 10 is V-shaped, and
the thread form 24 on the lower threading portion 12 is
square-shaped. FIG. 3 shows the threading groove on rod 10 if it
were to be unwound into a straight path. At points (a) and (b),
transverse cross-section views of the groove (turned 90.degree.)
are shown. At point (a) on the lower threading portion 12 of rod
10, the cross-section view shows the square-shaped thread form; at
point (b) on the upper threading portion 14 of rod 10, the
cross-section view shows the narrower V-shaped thread form.
[0042] FIG. 4 shows an example of a signal nut of the present
invention, in the form of a red-colored or another suitable colored
disc 30 which has a threaded hole 32 through which the rod 10 is
inserted. The disc 30 has two spring arms 34 that flex radially
outward against a fixed object inside the housing to keep the disc
30 stationary in the housing until the signal nut becomes
rotationally locked to the piston rod 10 and the torque applied to
the piston rod, and thereby to the signal nut, overcomes the
holding force provided by the spring arms 34. The spring arms 34
may have detent projections that mate with corresponding
depressions on the inside surface of the housing or another
stationary component, to keep the disc 30 stationary until it
becomes rotationally locked to the piston rod 10 and sufficient
force is applied. FIG. 5 shows a cross-section view of the internal
threading of hole 32. Viewed together with FIG. 3, this
demonstrates that the thread form of the internal threading in hole
32 has a square-shape that mates with the square-shaped thread form
24 of lower threading portion 12 of rod 10, but interferes with the
narrower V-shaped thread form 22 on the upper threading portion
14.
[0043] FIG. 6 shows the piston rod 10 inserted through threaded
hole 32 of disc 30. Disc 30 is initially located on a lower
threading portion 12 of rod 10 (below transition point 16). At this
position, because the internal threading on disc 30 mates with the
lower threading portion 12 on rod 10, piston rod 10 is freely
rotatable through disc 30. As the piston rod 10 screws down through
disc 30, the position of the threads of the piston rod 10 relative
to the disc 30 changes, such that the upper threading portion 14 of
rod 10 moves toward the disc 30. When the upper threading portion
14 of rod 10 reaches the disc 30, the V-shaped threading on this
portion of rod 10 interferes with the internal threading on disc
30. This blocks the rod 10 from further rotating through the disc
30, such that further rotation of the rod 10 will carry the disc 30
with it.
[0044] FIGS. 7-9 show an example of the functioning of one
embodiment of a medication injector of the invention. As shown in
FIG. 7A, the medication injector comprises a housing 50 (shown in
cross-section). At the top of the medication injector, there is a
dosage selection knob 54 that the user turns to dial the desired
dosage amount. The housing 50 contains the piston rod 10 with disc
30 threaded thereon.
[0045] A drive mechanism 52 drives the piston rod 10 down during
the dispensing of each dose. In one embodiment, the drive mechanism
52 includes a piston rod drive which rotates the piston rod 10 and
a stationary threaded bushing (not shown) through which the piston
rod 10 rotates. As the piston rod drive rotates, the piston rod 10
is caused to rotate, which, by virtue of the threaded engagement
with the threaded bushing, feeds the piston rod 10 forward to
dispense the medication. This threaded bushing allows free rotation
of the piston rod 10 on both of its thread forms. The drive
mechanism 52 may include other components, as explained above.
Examples of drive mechanisms that can be used with the invention
include those used in the SoloSTAR.RTM.-type medication injectors
and those described in U.S. Pat. No. 7,918,833, U.S. Pat. No.
7,291,132, and WIPO Publication WO 99/38554, which are incorporated
by reference herein.
[0046] Loaded into the distal portion of housing 50 is an ampoule
or syringe 60 that contains a liquid medication 66 for dispensing
through needle 64. The liquid medication 66 is pushed forward by a
stopper 62, which is driven by the distal end of piston rod 10.
There is a cut-out window 56 on a lower portion of the housing 50.
As seen in the side view of FIG. 7B, the ampoule or syringe 60,
stopper 62, and piston rod 10 are visible through cut-out window
56. At this point, the alert indicator, which is disc 30, is in a
hidden position in which it is generally not visible through the
window 56, and thus the disc 30 cannot be seen in FIG. 7B.
[0047] FIG. 8 shows the medication injector after several
injections. With each successive injection, more of piston rod 10
is advanced forward. Therefore, the length of the piston rod 10
that has been fed forward represents the total amount of medication
66 that has been dispensed thus far. As seen here, the piston rod
10 has been advanced forward and pushed down stopper 62. However,
the position of disc 30 has not changed, which is at this point is
still held in place by spring arms 34 that flex outward against the
inside wall of housing 50. The transition point 16 on rod 10 has
not yet reached the disc 30, and the disc 30 remains in the hidden
position.
[0048] FIGS. 9A and 9B show the medication injector after several
more injections and in a near-empty state. The piston rod 10 has
advanced further, and the transition point 16 on rod 10 has reached
the disc 30. Accordingly, in the manner already explained above,
the internal threading on disc 30 now has an interfering
interaction with the V-shaped thread form on the upper threading
portion 14 of rod 10. This causes the disc 30 to become
rotationally locked to the piston rod 10. Under the driving force
of the piston rod 10, the engagement of spring arms 34 on disc 30
against the inside wall of housing 50 holding disc 30 in place is
overcome. Thus, disc 30 travels downward with rod 10 such that disc
30 becomes visible through the cut-out window 56 in housing 50. As
can be seen in FIG. 9B, the alert indicator, which is disc 30, has
been moved from the hidden position to the visible position in
which it is visible through the window 56. This alerts the user
that the medication injector is in near-empty condition. Once
alerted by the alert indicator, the user can then read the dosage
scale and check the amount of medication remaining in the pen. If
the remaining amount is insufficient to deliver the full dosage
requirement, the user can retrieve a new medication injector (or
new medication cartridge for reloading the medication injector)
from the refrigerator and warm it room temperature so that it can
be used to supplement the final dose from the nearly-depleted
medication injector (or medication cartridge).
[0049] In the above-described embodiment, the spring arms 34 on
disc 30 drag against the inner wall of housing 50 to prevent the
disc 30 from rotating down on piston rod 10, which might give the
appearance of a broken or disconnected part. But in an alternate
embodiment, the spring arms 34 on disc 30 may be designed to avoid
dragging against the inner wall of housing 50 (or other component)
as the disc 30 is released from its stationary restraint and
advanced downward. In this case, when disc 30 is released from its
stationary hold, it may spin freely downward on rod 10 under the
force of gravity to bring the disc 30 into a position where it is
visible to the user. This may give a more dramatic visual signal to
the user that the medication injector is near-empty. Moreover, the
disc 30 may be sized to be smaller than the diameter of syringe 60.
With this design, when disc 30 spins down on rod 10, the disc 30
would come to rest on top of stopper 62.
[0050] In another embodiment of the invention, FIG. 10 shows a
cartridge holder portion for a medication injector. Inside the
cartridge holder, there is a medication cartridge made of
transparent glass and a piston rod 40 that is visible through the
glass. The cartridge holder portion is made of transparent plastic
and has a window 48. When the red (or another suitable color) disc
30 comes into view, it is visible through the window 48 as well as
through the transparent cartridge holder. The dosage scale 42 on
the medication cartridge is also visible through the transparent
cartridge holder. The level at the bottom of the flange of rod 40
is the dosage amount remaining in the medication cartridge.
[0051] The medication cartridge has a narrower dosage scale than
conventional cartridges. As shown in FIG. 10, the dosage scale
measures only the final 90 units of medication in the cartridge.
Having a narrower dosage scale can be advantageous because it helps
to draw attention to the dosage scale when the injector is
approaching empty. Moreover, to highlight the final (or near-final)
dosage amount, the last 60 units may be marked in red color (or
another suitable color) (bracket 46) compared to the black color
markings for the dosage amount above 60 units (bracket 44).
[0052] As such, in some embodiments of the medication injector, the
injector has a dosage scale that measures the amount of medication
contained in the medication cartridge, and the maximum amount
measured by the dosage scale is 120 units or less. For example, the
dosage scale may be limited to a range of 0 to 90 units or limited
to a range of 0 to 60 units. In some embodiments, a lower range of
the dosage scale is shown in a different color than an upper range
of the dosage scale. For example, in the dosage scale, the dosage
range of 60 units and less can be marked in a different color
(e.g., red color) than the markings for the dosage amounts greater
than 60 units (e.g., black color).
[0053] In some embodiments, a lower range of the dosage scale has
markings in finer resolution increments than an upper range of the
dosage scale. For example, in the dosage scale, the dosage markings
in the range of 0 to 60 units can be in finer resolution (e.g.,
increments of 10 units) than the dosage markings above 60 units
(e.g., increments of 30 units). This can allow the user to more
precisely measure the final (or near-final) dosage amount to be
injected.
[0054] FIG. 11 shows a partial view of an alternate embodiment of a
medication injector in which the piston rod 90 has a different
color on an upper portion 92 than on a lower portion 96 of the rod
90. As the piston rod 90 advances downward, appearance of the
differently-colored upper portion 92 through window 80 and the
transparent cartridge holder signals to the user that the injector
is near empty.
[0055] While certain embodiment illustrated herein have been
described with respect to a piston rod that rotates during dose
delivery, it will be understood that an alert indicator according
to the invention can be utilized with a piston rod that advances
axially without rotation during dose delivery. The piston rod may
have an alternative catch mechanism to the interfering threads as
previously described. For example, the piston rod may have a lug,
abutment, tab or other catch mechanism near its proximal end. The
alert indicator or signal nut may have a mechanism for temporarily
holding the alert indicator or signal nut in place until the catch
mechanism of the piston rod advances far enough to engage and
dislodge the alert indicator or signal nut. Alternatively, a piston
rod that advances axially without rotation during dose delivery may
have an upper portion with a different color, similar to the
embodiment of FIG. 11, wherein the differently-colored portion
serves as the alert indicator.
[0056] In some embodiments, the medication injector of the present
invention includes instructions for use that instruct the user to
read the remaining dosage amount in the medication cartridge (at
the distal edge of the stopper) when the alert indicator appears
and confirm whether this amount is sufficient for the full dose
that the user requires. The medication injector of the present
invention can be used to inject insulin or any other medication
that is administered by injection.
[0057] The foregoing description and examples have been set forth
merely to illustrate the invention and are not intended to be
limiting. Each of the disclosed aspects and embodiments of the
present invention may be considered individually or in combination
with other aspects, embodiments, and variations of the invention.
In addition, unless otherwise specified, the steps of the methods
of the present invention are not confined to any particular order
of performance. Modifications of the disclosed embodiments
incorporating the spirit and substance of the invention may occur
to persons skilled in the art, and such modifications are within
the scope of the present invention.
[0058] While the present invention is described herein with
reference to illustrated embodiments, it should be understood that
the invention is not limited hereto. Those having ordinary skill in
the art and access to the teachings herein will recognize
additional modifications and embodiments within the scope thereof.
Therefore, the present invention is limited only by the claims
attached herein.
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